As the office automations are progressed these days, many image forming devices, such as printers, copiers, fax machines, and multifunction printers, have been installed in offices in a concentrated or distributed layout, where the image forming devices are usually connected to a server via a network. Locations vary in installing those image forming devices including printers, copiers, fax machines, and multifunction printers. Some locations may offer an unfavorable environment for the image forming devices to operate. Particularly, when a daylong environment or a year-round environment changes greatly, the image forming devices are exposed to a constant risk of bedewing.
At offices and schools, sometimes a large volume of printed matters have to be prepared within a certain period. In such a case, a distributed printing system is employed to carry out division printing by grouping a plurality of the image forming devices, instead of using only one image forming device.
Environmental conditions for locations where image forming devices are installed vary widely at large offices, schools, etc. Some locations are in high temperature and others are in low temperature, and some are in high humidity and others are in low humidity, and some locations have a large fluctuation in temperature and humidity. Quite a few locations are not preferable for installation, and some measures for preventing the devices from bedewing is required for the location where temperature and humidity changes fiercely. Particularly, an electrophotographic image forming device is equipped with photosensitive drums, charged rollers, transfer rollers, optical lenses, dustproof glasses, and the like, and bedewing those equipment results in the formation of a blur or blot on a formed image that deteriorates image quality substantially, or causes a device failure.
Such a phenomenon as bedewing happens when photosensitive rollers or the like cooled at night touches the fresh air heated by a heater or the like, especially tends to happen just after the start of the device in winter. Image forming devices, therefore, must be under constant monitoring in terms of installation environment, and a bedewed or possibly bedewed image forming device must be excluded from printing operation.
The electronic copier disclosed in Japanese Laid-Open Patent Publication No. 60-76759 offers a technique for preventing bedewing on an image forming device. This copier detects temperature and humidity inside and outside a copier body, and actuates a bedewing preventive heater inside the copier when external humidity reaches a value corresponding to a saturated steam pressure value at an internal temperature.
In another case, the image forming device disclosed in Japanese Laid-Open Patent Publication No. 11-38861 has an exhaust means that exhausts air in the device to the outside, a means that detects an external temperature, and a means that detects an internal temperature. This image forming device controls the output of the exhaust means in response to a difference between the internal temperature and the external temperature, which is detected by the temperature detecting means.
The installation environment monitoring device for a printing device disclosed in Japanese Laid-Open Patent Publication No. 2005-165036 offers a technique for monitoring an installation environment for an image forming device. The installation environment monitoring device comprises a detecting means that detects an environmental parameter indicating the environment of an installation location for the printing device, a judging means that judges on whether the environmental parameter is within the range of a prescribed environment permissible value or not, a message creating means that creates a message informing of a judgment that the environmental parameter is not within the range of the environment permissible value when the judging means makes that judgment, and a communication means that transmits the message created by the message creating means to an external apparatus.
According to the optimum distributed printing system disclosed in Japanese Laid-Open Patent Publication No. 11-194911, the report printing capacity of each printing device is estimated to allow a plurality of grouped printing devices to exert their full capacity as a whole and enable printing of multiple reports in a shortest time. In this system, a printing server calculates a time each printing device takes to output printing data on the basis of printing capacity data of each printing device that is a candidate for distributed job assignment. With the calculated output time, the printing server optimizes the distribution of printing data so that each printing device finishes individual printing job at the same time, and assigns distributed data to each printing device, then gives printing instruction.
According to the conventional image forming devices as described above, individual judging means attached to each image forming device judges a state for bedewing independently. The conventional image forming devices, therefore, offers no uniform judging method, thus makes judgments that cannot be considered to be reliable enough. Such image forming devices are not appropriate to be interconnected via a network to construct a printing system.
A conventional image forming device provided with a bedewing preventive device is so constructed as to actuate the bedewing preventive device in advance when there is a concern of bedewing in the device. SO, it is not preferable from the point of energy saving for the case that a lot of image forming devices are connected in network because the power consumption for preventing bedewing becomes larger.
When a large volume of printed matters are prepared quickly by distributed printing, image forming devices have to be used as many as possible. If image forming devices not satisfying a given operational environmental condition, such as ones in a bedewing state, are not used but only the image forming devices satisfying the given operational environmental condition are used, the number of image forming devices to be used decreases and that makes it impossible to meet a requirement for printing in a shortest time.
When the individual judging means attached to interconnected each image forming device independently judges whether or not bedewing is developing in the device or whether or not the installation location environment of the device satisfies a given environmental condition, the judgment becomes less reliable because the criteria for the judgment is not uniform. Such image forming devices, therefore, are not appropriate to be interconnected via a network to construct a printing system.